What was studied 80 healthy menstruating women aged 20 to 49 who reported low sexual drive took 600 mg a day of a standardised fenugreek seed extract (Libifem) or a placebo for two menstrual cycles. Sex hormones and sexual-function questionnaires were measured at the start and at 8 weeks.

What was found Free testosterone and estradiol rose in the fenugreek group compared with placebo, and sexual desire and arousal scores improved.

What it means here A study of hormones and sexual function, not of breast size. The extract was a specific standardised product at 600 mg a day, not the 4:1 seed extract in Bust Bunny, and the finished product was not studied.

Source: Influence of a Specialized Trigonella foenum-graecum Seed Extract (Libifem), on Testosterone, Estradiol and Sexual Function in Healthy Menstruating Women, a Randomised Placebo Controlled Study. Phytotherapy Research, 2015 (randomised controlled trial).

Also noted: An animal study: fenugreek in the diet of lactating rats raised milk-synthesis gene activity. Not a human or breast-size study. Fenugreek Stimulates the Expression of Genes Involved in Milk Synthesis and Milk Flow through Modulation of Insulin/GH/IGF-1 Axis and Oxytocin Secretion, Genes, 2020.

What was studied 170 women with premenstrual syndrome took one tablet a day of a dry Vitex agnus-castus fruit extract (Ze 440) or a placebo for three menstrual cycles. They rated irritability, mood, anger, headache, breast fullness and bloating.

What was found Symptoms improved more with Vitex than with placebo: 52% of the Vitex group responded (at least a 50% reduction) against 24% on placebo. Side effects were mild and similar in both groups.

What it means here A premenstrual-symptom study. Breast fullness here means cyclical tenderness, which the extract relieved; it did not increase breast size. The extract was Ze 440, not the capsule blend, and the finished product was not studied.

Source: Treatment for the premenstrual syndrome with agnus castus fruit extract: prospective, randomised, placebo controlled study. BMJ, 2001 (randomised controlled trial).

Also noted: A 2023 review of small studies on Vitex and prolactin, a pituitary hormone, in people with raised levels. Vitex agnus castus effects on hyperprolactinaemia, Frontiers in Endocrinology, 2023.

What was studied 46 postmenopausal women in a 16-week randomised trial ate a daily muffin containing 25 g of ground flaxseed, 25 g of soy flour or a placebo. Urinary estrogen metabolites, blood hormones and bone markers were measured.

What was found Flaxseed raised urinary 2-hydroxyestrone and shifted the metabolite ratio toward the less active estrogens, more than soy did. Blood estrogen levels and bone markers did not change.

What it means here A small diet study of how estrogen is metabolised, at 25 g a day of ground seed, a food dose rather than a capsule dose. It did not measure breast tissue, and the finished Bust Bunny product was not studied.

Source: Supplementation with flaxseed alters estrogen metabolism in postmenopausal women to a greater extent than does supplementation with an equal amount of soy. The American Journal of Clinical Nutrition, 2004 (randomised controlled trial).

What was studied 71 postmenopausal women with hot flashes took dong quai on its own or a placebo for 24 weeks. Endometrial thickness, vaginal cell maturation, hot flashes and the Kupperman symptom score were measured.

What was found No differences between dong quai and placebo in endometrial thickness, vaginal cells, number of hot flashes or symptom score.

What it means here A null result: used alone, dong quai did not show estrogen-like effects on tissue and was no better than placebo for symptoms. It is listed for completeness and does not support a hormonal effect. The finished Bust Bunny product was not studied.

Source: Does dong quai have estrogenic effects in postmenopausal women? A double-blind, placebo-controlled trial. Fertility and Sterility, 1997 (randomised controlled trial).

What was studied 80 postmenopausal women aged 45 to 60 in Iran were randomised to 2 g of fennel seed powder in capsules daily or a starch placebo for 8 weeks. Menopausal symptom score, sexual desire and serum estradiol were measured.

What was found The menopausal symptom score fell more in the fennel group (30.8 to 19) than with placebo (31.2 to 26.4). Estradiol levels and sexual desire did not differ significantly between the groups.

What it means here A symptom study in postmenopausal women in which hormone levels did not change. It is not a study of breast tissue, and the finished Bust Bunny product was not studied.

Source: The effect of Fennel seed powder on estradiol levels, menopausal symptoms, and sexual desire in postmenopausal women. Menopause, 2020 (randomised controlled trial).

What the source is The NIH's National Center for Complementary and Integrative Health summary of the research on menopausal symptoms, which covers wild yam among other supplements.

What it says It states that very little research has been done on wild yam for menopausal symptoms, so no conclusions can be reached about its effectiveness.

What it means here There is no clinical trial of oral wild yam root to point to; the one small trial in the literature used a skin cream. Bust Bunny includes wild yam root as a traditional ingredient, and the finished product was not studied.

Source: Menopausal Symptoms: In Depth. National Center for Complementary and Integrative Health (NIH) (government fact sheet).

What was studied 304 women with menopausal symptoms in a randomised, multicentre, double-blind trial took tablets equal to 40 mg a day of an isopropanolic black cohosh extract, or a placebo, for 12 weeks. The Menopause Rating Scale was the main measure.

What was found The extract was more effective than placebo, with the hot-flush score responding most; women early in menopause benefited more. Side effects did not differ from placebo.

What it means here This tested a specific isopropanolic extract (Remifemin type), not an extract standardised to 2.5% triterpenes like the one in Bust Bunny. A larger 12-month US trial of a 2.5% triterpene extract found no benefit over placebo (below), and the NIH says the evidence is insufficient overall. The finished product was not studied.

Source: Efficacy and safety of isopropanolic black cohosh extract for climacteric symptoms. Obstetrics and Gynecology, 2005 (randomised controlled trial).

Also noted: 351 women, 160 mg a day of a 2.5% triterpene glycoside extract for 12 months: hot flashes did not differ from placebo. Summarised in the NIH Office of Dietary Supplements black cohosh fact sheet. Treatment of vasomotor symptoms of menopause with black cohosh, multibotanicals, soy, hormone therapy, or placebo: a randomized trial, Annals of Internal Medicine, 2006.

What the source is The European Medicines Agency's herbal monograph on blessed (holy) thistle, the EU's assessment of its traditional use.

What it says It records traditional use for temporary loss of appetite and mild digestive complaints. No clinical trial of blessed thistle on its own is listed; the NIH LactMed database likewise notes no scientifically valid trials for its use in lactation.

What it means here A traditional-use record, not evidence of a hormonal or breast effect. Bust Bunny includes blessed thistle as a traditional ingredient, and the finished product was not studied.

Source: Cnici benedicti herba (holy thistle): European Union herbal monograph. European Medicines Agency, 2024 (regulatory monograph).

What was studied A 2019 update of the European Medicines Agency's 2010 assessment of motherwort (Leonurus cardiaca), covering research published from 2010 to 2018.

What was found The herb has a documented traditional use for heart complaints and for gynaecological conditions such as painful periods and menopausal anxiety. The review summarises early laboratory and clinical evidence and calls for further research.

What it means here A literature review of traditional use and early evidence, not a clinical trial. The finished Bust Bunny product has not been studied.

Source: Leonurus cardiaca L. as a Source of Bioactive Compounds: An Update of the European Medicines Agency Assessment Report (2010). BioMed Research International, 2019 (review).

What was studied 75 postmenopausal women with raised blood lipids in a 6-month randomised trial: 39 took 40 mg of red clover isoflavones twice daily and 36 took a starch placebo. Menopause Rating Scale scores and cholesterol were measured at 3 and 6 months.

What was found Menopause symptom scores, total cholesterol, LDL and triglycerides fell, and HDL rose, more with red clover than with placebo at most time points.

What it means here A study of menopausal symptoms and cholesterol using 80 mg a day of concentrated isoflavones, not 80 mg of herb. Other trials of red clover isoflavones have had inconsistent results, as the NIH notes. It did not measure breast tissue, and the finished Bust Bunny product was not studied.

Source: Isoflavones obtained from red clover improve both dyslipidemia and menopausal symptoms in menopausal women: a prospective randomized placebo-controlled trial. Climacteric, 2024 (randomised controlled trial).

What was studied 240 adults at two sites, 188 of whom completed the study, drank a freeze-dried watercress drink three times a day for 2 weeks and a placebo drink for 2 weeks in random order. The watercress supplied about 40 mg a day of PEITC, a natural mustard-oil compound; urinary detoxification products of several toxicants were measured.

What was found Urinary detoxification products of six of seven toxicants rose significantly on watercress, most for acrolein (66%) and benzene (37%).

What it means here A study of how the body clears environmental toxicants, with no hormone or breast endpoint. It says nothing about breast enhancement. Bust Bunny includes the aerial parts of watercress in a much smaller amount, and the finished product was not studied.

Source: A watercress drink increases detoxification of common environmental carcinogens such as acrolein and benzene: results of a randomized clinical trial. Carcinogenesis, 2025 (randomised crossover trial).

What was studied 120 women with early menopausal symptoms were randomised to hop tablets or a placebo for 12 weeks. Symptoms were scored on the Greene scale and hot flashes recorded in a diary at 4, 8 and 12 weeks.

What was found Greene scores and hot-flash counts were significantly lower in the hop group at every check, with the gap widening to 12 weeks.

What it means here A single trial of a standardised hop tablet (reported as 100 µg a day of the hop phytoestrogen 8-prenylnaringenin), not hops powder, and its effect was much larger than in earlier trials, so it should not be read as settled. Hops was studied for menopausal symptoms, not breast size. The finished product was not studied.

Source: The effect of Hop (Humulus lupulus L.) on early menopausal symptoms and hot flashes: A randomized placebo-controlled trial. Complementary Therapies in Clinical Practice, 2016 (randomised controlled trial).

Also noted: 67 women: the 100 µg 8-prenylnaringenin dose beat placebo at 6 weeks but not at 12, and the higher dose was not better. A first prospective, randomized, double-blind, placebo-controlled study on the use of a standardized hop extract to alleviate menopausal discomforts, Maturitas, 2006.

What the source is The NIH Office of Dietary Supplements fact sheet on vitamin C, a government summary of the evidence rather than a single trial.

What it says Vitamin C is required to make collagen, the protein of connective tissue and skin, and is an antioxidant that also supports immune function and iron absorption. The adult recommended intake is 75 to 90 mg a day; the upper limit for adults is 2,000 mg.

What it means here A two-capsule serving of Bust Bunny provides 475 mg (528% of the Daily Value), within the upper limit. The fact sheet makes no claim about breast size, estrogen or skin firmness, and the finished product was not studied.

Source: Vitamin C: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements (government fact sheet).